How to Use a Rocket Mass Heater to Cook & Heat Off-Grid
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Learn how to heat and cook off-grid with a rocket mass heater, and why this is an even more energy-efficient solution than a traditional wood stove!
This is a guest post by Sunflower Craig of Permies.com
For many, wood heat and wood burning stoves conjure up nostalgia and cozy feelings. After reading this, next time you think of wood heat, you’ll also think of the words “eco-friendly,” “affordable” and “efficient,” (and maybe even “pizza!”) If you’re searching for a strategy to save money and protect the environment without having to sacrifice luxury, wood heat is the way to go.
A particularly eco-friendly choice, wood heat uses a renewable fuel source. Wood, in contrast to fossil fuels, has the potential to be an endless supply. If we keep forests healthy and keep planting trees, people can use wood for warmth for centuries to come. Despite naysayers and vocal activists, combining good woodland practices and an extremely efficient wood stove could actually have a negative carbon impact.
Wood heat is frequently more cost-effective than other forms of heating, such as gas or electricity. Surprise! Not only can you save the environment, but you can save money by using wood heat to warm your house.
So what is the best way to heat your home with wood? If you’re lucky enough to have a wood-burning fireplace or a wood stove, those are the most well-known and conventional methods for heating your home with wood. But have you ever heard of a rocket mass heater?
A rocket mass heater has one tenth the carbon footprint of a conventional wood stove. Rocket mass heaters allow you to both heat your home and cook in an efficient manner that is good for the environment and that doesn’t rely on the power grid. Not to mention, as energy costs continue to rise, rocket mass heaters offer a more affordable solution to keeping warm.
What is a rocket mass heater?
There are a few variations of rocket heaters and cooking equipment, including rocket stoves, rocket ovens, rocket water heaters and, of course, rocket mass heaters.. The first and most basic version is the rocket stove, which is used primarily for cooking. A rocket stove can be as simple as using a tin can and some stove piping or stacking bricks to make a basic but highly efficient DIY rocket stove. Check out the video below for a step-by-step tutorial on how to build your own DIY brick rocket stove for outdoor or off-grid cooking. Alternatively, you can purchase a rocket stove for a pretty affordable price so you at least have it in case of an emergency.
Rocket mass heaters are the next level up from rocket stoves. They consist of a fire or burn box, an insulated combustion chamber that burns fuel at very high temperatures, and a thermal mass -typically made out of cobb and stone- attached to the exhaust pipe, which snakes through the thermal mass before connecting to the chimney pipe. Due to their highly efficient design, rocket mass heaters are more energy efficient and environmentally friendly than other types of wood heat; They burn at a higher temperature, emit practically no smoke at all, and charge the thermal mass around them. Not to mention, rocket mass heaters require much less fuel than conventional wood stoves or fireplaces. Some estimates even say rocket mass heaters can reduce fuel consumption by up to 90 per cent!
In the end, burning just a small amount of fuel for a short amount of time leaves your home nice and toasty for up to a day or more after you’ve heated up your rocket mass heater. Given that they are smokeless, they can also provide a more discrete manner of heating your home. They are especially significant in that you can use whatever wood fuel you’ve got lying around: branches, twigs yard waste and other scrap burnables. You can even burn those astronomical heating bills;);)
After all, there is a heating crisis happening in many parts of the world; and this may well be a problem that will continue over the next few years. Heating costs are skyrocketing, leaving many people choosing between heating their home and buying groceries. But there is hope! You never have to heat your home the same, costly way again. Rocket Mass Heaters offer a solution for maximum efficiency and minimal pollution.
How does a rocket mass heater work?
Rocket mass heaters differ from wood stoves in that wood stoves typically heat up to around 1000ºF, with much of the heat escaping up the chimney along with the smoke. The chimneys on wood stoves are highly insulated to allow for the high temperatures, which are needed to burn off the creosote that builds up in the chimney. Rocket mass heaters, on the other hand, have an insulated fie box and combustion chamber which not only allows the temperature to rise up to 1800ºF, but also combusts all of the creosote as well as all of the smoke before it has a chance to escape through the chimney. The result is a warmer home, less energy waste and less smoke and creosote buildup in your chimney and in the atmosphere.
The exhaust pipes then travel through the thermal mass that’s attached to the rocket heater until finally escaping through the chimney piping. This thermal mass continues to radiate heat for many hours after the initial burn, which heats your home for longer using much less fuel.
In short, rocket mass heaters are more efficient than conventional wood stoves because they keep more heat inside your home.
Here’s a short video that illustrates exactly how this process works:
For a more detailed look into how rocket mass heaters work, Ernie and Erica Wisner, rocket mass heat pioneers, go into far more detail about the fire science involved in rocket mass heaters. They cover the science, but also the making of pocket rockets, the explosive properties of steam, and the most efficient rocket mass heater design of the time. (You can see this in the movie “Better Wood Heat: DIY Rocket Mass Heaters.”)
Other uses for rocket mass heaters
The applications of the rocket mass heater extend far beyond just heating your home.
Rocket mass heaters are versatile for lots of situations, including:
- a cozy place to sleep in a tipi
- a place to warm your butt around the campfire without smoke in your face
- a stove to cook on
- an efficient ways to heat your home
- a source for hot water
- even an oven for baking pie! Mmm, pie…
In the forums of Permies.com, members have created rocket forges, saunas, cooktops and smokers, water heaters and more, and have extended their growing season by using a rocket heater to directly heat their soil, or to heat their greenhouse.
At Wheaton Labs in Montana, rocket technology is pervasive. The folks at the lab have built a pizza oven which rivals even the best wood-fired pizza restaurants. They heat the water for their shower with the rocket water heater and have even figured out how to extend the gardening season with a rocket mass heater!
Australian alternative energy innovator Tim Barker built a stand alone rocket water heater, rocket oven and rocket griddle at the 2015 Rocket Mass Heater Jamboree at Wheaton Labs. Tim is well known for his safe and efficient rocket water heaters and has taught the appropriate technology course at Wheaton Labs in the past and now teaches Appropriate Technology at the Koanga Institute.
But let’s go back to that pie! If having a way to cook off-grid is important to you, our rocket oven DVDs show you in detail how to build your own rocket oven to cook or bake in. You can make your own wood-fired pizza, delicious pie, homemade bread, roasted meat, baked lasagna, cookies, cakes and more with a rocket oven. Learn more right here.
Good food, a nice warm home and clean, cheap, luxuriant heat. And the peace of mind of never having to worry about how to heat your home again.
If you’re ready to take a giant leap toward more energy independence and stop worrying about rising energy costs, power outages, emergencies and other threats to “the grid,” come visit us at Permies.com where we talk about about rocket mass heaters, off-grid living, homesteading, permaculture and more!
And if you’ve ever built or used a rocket mass heater before, be sure to share your thoughts or experience in the comments section below!
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